The Motorcraft 2150 was produced from 1973 to 1983. The 2150 came out in response to the newer smog controls put in place in the early 70’s. You will find the 2150, 2 barrel a bit more complicated than the older 2100, 2 barrel.
When the tag is missing there is no way to identify the carburetor number.
In the case of a missing tag, take the carburetor apart and match all parts with the pictures we have for each carburetor kit. We can help with this if needed.